A nuclear reactor created for Eisenhower's "Atoms for Peace" campaign is now used for research at a Dutch university.

A surprisingly detailed model of one of the most powerful telescopes in the world.

A catapult rock from Gotland’s 13th-century civil war is still lodged in Scandinavia's best-preserved medieval city wall.

Wind power station for making famous Ketel One vodka.

Rich with fauna and flora, nature-lovers can walk across the sea at this UNESCO World Heritage spot.

This imposing tower named after the mythical sword of King Arthur is considered the tallest freestanding climbing wall in the world.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

Colorful and chaotic stacked hotel in North Holland.

Frequent fliers welcome in this airplane hotel.

Once the world's biggest telescope, it was later used as a coat hanger by a famous Dutch astronomer.

This fantastic cave remained unexplored until 1948 when three schoolboys discovered a hidden entrance.

Known locally as the Jungfrutornet, this Medieval tower hides a dark legend.

A golden plaque marks the site of the mysterious unsolved assassination of the former Swedish prime minister.

Visit the home of Sweden's beloved fictional character, Pippi Longstocking.

A lone cannonball remains lodged in the walls of the Hotel de Sens as a sober reminder of a revolution.

Public access to clean drinking water was an instant hit among the masses.

One part local history, 99 parts gruesome haunted house.

On October 17, 1814, a 15-ft. wave of beer ran rampant through the streets of London.

This luxury shopping lane has been protected by its own tiny police force for over a century.

Installed at a chaotic intersection, this gave London traffic cops a place to hang their heavy woolen coats.

Legend has it that this large rock maze in Sweden was created as punishment by the daughter of a wealthy captain.

This trio of stone spires claims to be the only preserved medieval execution site in Europe.

Ancient stone graves shaped like ships provided a Viking-like burial to carry the dead to the afterlife.

Hidden in plain sight, Sweden's official ordnance datum is now abandoned.